Balancing device



CCL 23, 1951 G. w. JOHNSON BALNCING DEVICE Filed Feb. lO

` .I2 l 7 941 0 2 m c f x 2 .0 3 w la 5 3 l 4, l 2 s 4 l lg l PatentedOct. 23, 1951 2,512,265 BALANCING DEVICE George W. Johnson, Cincinnati,Ohio, assignor to The American Laundry Machinery Company, NorwoodStation, Cincinnati, h10, a corporationofOhio Y Application February10,'19479, Serial No. 75,535 claims. (cl. 74;-5'14) This inventionrelates to balancing devices, such as are used to dampen the vibrationsof rapidly rotating bodies. The invention is an improvement upon thatdescribed and claimed in my prior Patent No. 2,144,064 granted January17, 1939, for Balancing Device for Extractors.

While the invention is capable of use to reduce vibration of anyrotating body, it is'l here illustrated in typical from applied to acentrifugal extractor, the perforate basket of which is started andstopped frequently and carries a load which usually is or cannot bedistributed absolutely evenly about the central axis. The balancingdevice of my prior patent is driven by a source of power which isseparate and distinct from that which drives the basket.

One object of the invention is to provide for a rotating body'improvedbalancing or vibration damping means which automatically is acceleratedin advance of said body.

A further object is to provide an improved arrangementof. rotating bodyand vibration damping means therefor in which both are driven from thesame power source, but in a manner to accelerate the damping means inadvance of the rotating body.

Still another object is to provide improved driving connections for arotating body and vibration damping means therefor in which the rotatingbody and damping means are driven from the same source, one by a directconnection and the other through a slip or lost motion connection, sothat one is accelerated before the other.l

Another object is to provide an improved arrangement of rotating bodyand vibration damping means, both driven by the same power motor, onedirectly and the other through fluid clutch means, thus to accelerateone before the other.

Further objects of the invention in part are obvious and in part willappear more in detail hereinafter.

In the drawings,

Fig. 1 is a sectional elevation, showing one form of my inventionapplied to a centrifugal extractor;

Fig. 2 is a sectional plan view, from beneath, on the line 2-2, Fig. 1;and

Fig. 3 is a detail sectional elevation, on a larger scale, through thedriving shaft and fluid clutch.

In many respects, the extractor shown in the drawings to typify oneclass of devices to which the present invention may be applied is likethat of my prior patent referred to and requires but brief description.e

The extractor shown comprises a stationary curb I0, provided with ahinged cover I I, in which rotates a foraminous work holding basket ordrum I2 mounted upon the upper end of shaft I3 `Journalled in a bearingmember Il provided with the usual resilient mounting in rubber rings I5carried by support IG, enabling the shaft and basket to tilt to alimited amount as it rotates,

all as usual. On shaft I3 is mounted a pulley I'I 4driven by belt I8, itbeing understood that, as is usual, a drum portion I9 ,of the pulley mayserve as a brake drum for cooperation with suitable brake means Isa usedfor the purpose of quickly bringing the basket to rest when the power isshut olf.

Upon shaft I3 is rotatably mounted a sleeye- 20 to which the vibrationdamping member is attached. This is an annulus or ring 2I provided witha series of circumferentially spaced openings 22, in each of which ismounted a spiral spring 23 attached at its outer end to ring 2| and atits inner end to a bolt or stud 24 mounted on a circular plate or table25 integral with or attached to sleeve 20. A rubber ring 26 mounted inan annular groove 21 of ring 2l supports the ring 2I and relieves thesprings 23 of load other than in the generally horizontal direction. Arubber bumper 28 limits basket tilt.

Sleeve 20, at its lower end is provided with a pulley member 29 drivenby belt 30.

Referring to Fig. 3, the power source for driving or rotating both thebasket and the vibration damping ring 2I is an electric motor 3l mountedupon a boxlike side extension `32 of the extractor curb.

Motor shaft 33 drives member 2I by any suitable connecting means ofnon-slip form under normal operating conditions, so thatin starting andstopping, the motor and member 2| accelerate and deceleratesynchronously. Chain and sprocket connections would be suitable, butfrom the practical standpoint, a V-belt 30 traveling over driving pulley34 and a groove in sleeve 20 and tightened by a floating belt tighteningpulley 30a conventionally shown is satisfactory.

An lextension of shaft 33 is'used to drive belt I8, shaft I3 and basketI2. This driving connection includes means for insuring that when themotor is energized to start the extractor basket, the vibration dampingmember 2I is accelerated. and even reaches full speed, ahead of orbefore the loaded extractor basket. In other words, the rate ofacceleration of the basket is ret-arded, while that of member 2l issynchronous with the motor shaft. Any slipping connection may be usedfor the purpose.

The means shown is a fluid clutch, although other arrangements may beemployed. As shown, shaft I3 extends into the chamber of a sealed drumform casing 35, where it is provided with impeller vanes or paddles 36working in an oil bath 31 which fills the chamber. Opposite the varies36, the chamber wall carries vanes 33. Casing 35 is provided with ashaft 39 turning in a. bearing 40 and provided with a pulley Il whichdrives belt i8.

It should be noted that pulleys 34, Il are of approximately the samesize, while pulley I1 is considerably larger than pulley 29. The gearratios in the two trains from the motor shaft consequently differ and atfull speed ring 2i is driven at higher speed than the basket. But thegear ratios in the two trains are not important.

The operation is as follows:

Motor 3| may be either a single speed motor,

in which case, upon starting, it accelerates rapidly to full speed, or avariable speed motor manually controlled, in which case it acceleratesto the desired full speed in accordance with the manner of its manualcontrol. In either case, when starting lthe extractor, during the periodof acceleration of the motor to full speed, the vibration damping ring2l accelerates synchronously with the motor, or at the same rate. Thereis no slippage or lost motion between them. However, Vin

either case, during the same period of acceleration, shaft I3 and theextractor basket lag behind the vibration damping ring 2i. tion of thering is retarded.

Accelera- The first effect of motor shaft 33, within the fluid clutch,is to rotate the vanes 36 within the bath of oil or other liquidcontained in the casing.

At first, vanes 36 rotate without appreciable motion of the clutchcasing 35. However, the rotating effect is transmitted through theliquid bath to vanes 38, which begin to turn with the vanes 36 andgradually pick up speed until, in the end, as in all fluid or other slipclutches, the rotated clutch part travels at substantially the samespeed as the driving clutch part, subject to a. possible small net loss.

The purpose of balancing a vibration damping device of this kind is totake care of out of balance loadv conditions which tend to cause thebasket and its shaft to tilt to one side or the other and vibrate aroundthe true center of rotation. Consequent vibration, during acceleration,is considerably amplified at certain critical speeds of the basket andshaft. In practice it is found that by compelling acceleration of thevibration damping ring in advance of acceleration of the basket andshaft, the consequent roughness and unnecessary or undesirable vibrationare considerably reduced, if not entirely eliminated. In other words, instarting, if the unbalanced condition, either of the basket and shaftalone or of the basket and shaft and basket load, is not in unreasonableexcess, the present arrangement will-take care of it and bring thebasket to full speed, spinning quietly on a substantially stationaryaxis, in a short period, and Without undue roughness.

Of' course, the same effects occur in reverse order in stopping themachine. During deceleration, the basket and shaft usually are stoppedas quickly as possible, to save time, by the application of brake 19a tothe drum I9. The consequent braking eiect quickly decelerates the basketand shaft, but since the motor current has been shut off the motor shaftand the damping ring tend to coast freely and continue to dampenvibration of the basket and its shaft. Thus, in stopping deceleration ofthe damping ring is retarded, relative to deceleration of the basket andits shaft.

The invention, of course, may be applied to 4 other machines or devicesthan extractora, such as ilywheels and other rotating bodies.

l. In combination, a rotatable body, said bodyA having a portionconcentric with the axis of rota.- tion of the body, a rotatablecentripetal vibration damper of annular contour disposed generallyconcentric with said body portion and having free rotational contactwith said portion, a driving motor, there being a slip clutch drivingconnection between said motor and said body portion, and constant ratiodriving connection means for transmitting rotational torque from saidmotor to said vibration damper.

2. In combination, a rotatable body@l rotatable shaft aflixed to saidbody concentric with the axis of rotation thereof, vibration dampingmeans having a sleeve portion surrounding and rotatable independently ofsaid shaft, a motor for supplying rotational torque both to said shaftand to said sleeve, there being s. constant ratio driving connectionbetween said motor and said sleeve. anda slip clutch driving connectionbetween said motor and said shaft.

3. In lcombination with a rotatable body a driven shaft aflixed to saidbody in alignment with the axis of rotation thereof, vibration dampingmeans having a sleeve portion surrounding and in contact with said shaftand rotatable independently thereof, a driving shaft, means for rotatingsaid driving shaft, a constant ratio driving connection between saiddriving shaft and said sleeve portion, and a slip clutch drivingconnection between said driving shaft and said driven shaft.

4. In combination with a rotatable body a driven shaft affixed to saidbody in alignment with the axis of rotation thereof, vibration dampingmeans having a sleeve portion surrounding and in contact with said shaftand rotatable independently thereof, a driving shaft, means for rotatingsaid driving shaft, a constant ratio driving connection between saiddriving shaft and said sleeve portion, and a slip clutch drivingconnection between said driving shaft and said driven shaft, said slipclutch connection comprising a uid clutch whereof the complementaryvaries are coupled respectively to the driving shaft and to the drivenshaft.

5. In combination, a rotatable body, a driven Vshaft affixed to saidbody in alignment with the REFERENCES CITED The following references areof record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,887,355 Kranick Nov. 8, 19321,993,405 Heitshu Mar. 5, 1935 2,144,064` Johnson Jan. 17, 19392,467,108 Barlow Apr. 12, 1949

